1. Field of the Invention
This invention relates to floatation devices. More particularly, the present invention relates to a lightweight, resilient, seamless pontoon having shape memory characteristics which make it partially self-inflating, and resistant to deflation even when punctured.
2. State of the Art
Lightweight and portable flotation devices, including pontoon boats, float tubes, etc., have become increasingly popular in recent years, particularly with sport fishermen and white water enthusiasts. Most of these devices rely upon inflatable tubes, pontoon, or bladders which comprise a thin, flexible membrane which is filled with pressurized air. These prior art devices are very lightweight and easily portable, and may be folded into a relatively compact shape. Prior art pontoons which are formed of a thin membrane such as vinyl are typically 0.015 inch thick. Others, such as polyurethane film are even thinner, such as about 0.009 inch. Such pontoons are generally uniform in thickness throughout, and are frequently sewn together from several flat pieces to form the tubular shape.
However, because they are relatively thin, typical float tubes and pontoons are highly susceptible to puncture, such as from snagging fish hooks, rocks, branches, etc. Additionally, the materials of their construction are typically sewn together, creating seams that present inherent weakness. Because of their thinness and pliability, when typical pontoons are punctured, they usually entirely collapse and lose their buoyancy. They can also be difficult to repair. Typical thin membrane pontoons are repaired in a manner similar to bicycle or automobile tires, using patches and chemical adhesives. Once repaired, the membrane may not be as strong as it was before.
Additionally, typical float tubes and pontoons are very susceptible to changes in temperature and barometric pressure. For example, many users first inflate their boat in the morning, when temperatures are cool. Then, by afternoon, when the ambient temperature has increased, the pontoon pressure will have increased such that air must be released from the pontoon to prevent it from bursting. Then when the temperature drops again toward evening, the pontoon pressure likewise drops, and the boat often no longer provides sufficient buoyancy.
Similarly, many boat users inflate their pontoons before leaving home, then drive into a mountainous region at much higher altitude. In the course of gaining altitude, the barometric pressure drops, and the relative pressure inside the pontoons increases, sometimes enough to cause the pontoon to burst.
The present invention overcomes many of the problems of the prior art by providing a pontoon comprising a seamless, non-woven, one-piece, inflatable vessel preferably formed by rotational molding, from a resilient, semi-rigid polyolefin elastomer, preferably metalocene. The pontoon has shape memory characteristics which make it partially self-inflating, and cause it to entrap air when partially deflated, to thereby resist complete deflation if punctured, allowing a user to more easily get to safety. Punctures in the pontoon may be easily repaired by applying heat to the polymer material at the site of the puncture, such as with a hot knife or other metal item, so as to re-fuse the polymer material together. The bottom of the pontoon is preferably thicker than the top, and the ends of the pontoon taper to a blunt point that is thicker still, to thereby resist damage from impact and to help maintain the desirable shape-memory characteristics of the pontoon. The pontoon is also more tolerant of significant relative pressure changes than typical thin membrane inflatable pontoons, without substantial deformation or change in its shape.
Specifically, a hand portable inflatable boat for floating a person in water comprises a seat, positioned to support a person on the boat; and at least one float, positioned to support the seat above the water, having a cavity formed within the float, designed to hold air and a wall, formed around the cavity, that has a shape memory in a form of a fully inflated float. Alternatively, a hand portable inflatable pontoon boat for floating a person in water comprises a seamless, non-woven, one-piece, inflatable vessel of resilient, semi-rigid polyolefin elastomer, having a top, a bottom and two ends which taper to a blunt point that is thicker than other portions thereof; wherein the vessel is configured to retain a shape memory of an inflated configuration, so as to be partially self-inflating and configured to entrap air when partially deflated, to thereby resist complete deflation. Next, a self-inflating float for use with a pontoon boat comprises a seamless, non-woven shell defining a cavity, wherein the shell is biased to form an expanded shape when pressure is equalized between the cavity and the air surrounding the shell; and a valve configured for allowing air in and air out of the cavity.
Other advantages and features of the present invention will be apparent to those skilled in the art, based on the following description, taken in combination with the accompanying drawings.